T-plotter: tool for plotting celestial lines of position

Abstract

The T-plotter is a T-shaped transparent plotting utensil consisting of two mutually perpendicular arms and equipped with a rotatable compass rose mounted on a shuttle sliding along its arm of symmetry. This device allows a simplified plotting of celestial lines of position according to the intercept method of Marcq St. Hilaire. The compass rose is used to dial in the required azimuth. The intercept distance is marked by sliding the shuttle to the appropriate distance from the top of the main body based on the latitude scale of the employed nautical chart.

I claim: 
     
         1 ) A transparent plotting utensil in the shape of the uppercase letter T, consisting of two mutually perpendicular arms, and whose arm of symmetry is marked with a central line. 
     
     
         2 ) A transparent shuttle marked with a central line, including a rotatable compass rose, and sliding on the arm of symmetry of the device defined in  claim 1 ).